I tutored grade school kids in math after school and was specifically told not to do “flash cards” or any rote facts. I was supposed to teach them fractions (reducing) without previous knowledge of multiplication facts!
Luckily, I slipped through an unapproved phonics program for reading and many of the kids having trouble reading picked it right up.
I met a chinese woman in college who had exceptionally good hand calculation skills. I asked her how she got so good, and she said in remedial math levels in china they do not allow electronic calculators period, they stress wrote memorization where appropriate, and require the use of such things as the babylonian method for quickly extracting roots by hand that are considered obscure by today’s high school level students.